Co-reporter:Wenhao Guan, Bin Pan, Peng Zhou, Jinxiao Mi, Dan Zhang, Jiacheng Xu, and Yinzhu Jiang
ACS Applied Materials & Interfaces July 12, 2017 Volume 9(Issue 27) pp:22369-22369
Publication Date(Web):June 2, 2017
DOI:10.1021/acsami.7b02385
Rechargeable sodium-ion batteries (SIBs) are receiving intense interest because the resource abundance of sodium and its lithium-like chemistry make them low cost alternatives to the prevailing lithium-ion batteries in large-scale energy storage devices. Two typical classes of materials including transition metal oxides and polyanion compounds have been under intensive investigation as cathodes for SIBs; however, they are still limited to poor stability or low capacity of the state-of-art. Herein, we report a low cost carbon-coated Na2FeSiO4 with simultaneous high capacity and good stability, owing to the highly pure Na-rich triclinic phase and the carbon-incorporated three-dimensional network morphology. The present carbon-coated Na2FeSiO4 demonstrates the highest reversible capacity of 181.0 mAh g–1 to date with multielectron redox reaction that occurred among various polyanion-based SIBs cathodes, which achieves a close-to-100% initial Coulombic efficiency and a stable cycling with 88% capacity retention up to 100 cycles. In addition, such an electrode shows excellent stability either charged at a high voltage of 4.5 V or heated up to 800 °C. The present work might open up the possibility for developing high capacity, good safety and low cost polyanion-based cathodes for rechargeable SIBs.Keywords: good safety; high capacity; low cost; Na2FeSiO4-based cathode; sodium-ion battery;
Co-reporter:Peng Zhou, Xiao Wang, Wenhao Guan, Dan Zhang, Libin Fang, and Yinzhu Jiang
ACS Applied Materials & Interfaces 2017 Volume 9(Issue 8) pp:
Publication Date(Web):January 19, 2017
DOI:10.1021/acsami.6b13613
Cost-effective sodium ion batteries (SIBs) are emerging as a desirable alternative choice to lithium ion batteries in terms of application in large-scale energy storage devices. SnS2 is regarded as a potential anode material for SIBs because of its unique layered structure and high theoretical specific capacity. However, the development of SnS2 was hindered by the sluggish kinetics of the diffusion process and the inevitable volume change during repeated sodiation–desodiation processes. In this work, SnS2 with a unique nanowall array (NWA) structure is fabricated by one-step pulsed spray evaporation chemical vapor deposition (PSE-CVD), which could be used directly as binder-free and carbon-free anodes for SIBs. The SnS2 NWA electrode achieves a high reversible capacity of 576 mAh g–1 at 500 mA g–1 and enhanced cycling stability. Attractively, an excellent rate capability is demonstrated with ∼370 mAh g–1 at 5 A g–1, corresponding to a capacity retention of 64.2% at 500 mA g–1. The superior sodium storage capability of the SnS2 NWA electrode could be attributed to outstanding electrode design and a rational growth process, which favor fast electron and Na-ion transport, as well as provide steady structure for elongated cycling.Keywords: anode; PSE-CVD; rate capability; SnS2 nanowall arrays; sodium ion batteries;
Co-reporter:Tianzhi Yuan; Yinzhu Jiang;Qiuting Wang;Bin Pan; Mi Yan
ChemElectroChem 2017 Volume 4(Issue 3) pp:565-569
Publication Date(Web):2017/03/01
DOI:10.1002/celc.201600588
AbstractThe realization of high-power lithium-ion batteries (LIBs) is heavily hampered by intrinsically slow lithium diffusion within solid electrodes. Capacitive-like lithium storage behavior observed in transition-metal oxide (TMO)-based anodes shed light on attaining battery-like capacity and supercapacitor-like rate performance simultaneously. Herein, “honeycomb”-like Mn2O3 films were successfully demonstrated as anodes for LIBs, in which the pseudocapacitive effect is strengthened upon cycling, resulting in a high-rate lithium storage capability. Such pseudocapacitance originates from the unique porous structure and cycle-induced microstructure evolution. The reticular Mn2O3 can reach 1584.9 mAh g−1 over 250 cycles at 1 A g−1, 1564.9 mAh g−1 after 500 cycles at 5 A −1, and 475.6 mAh g−1 at 15 A g−1.
Co-reporter:Yinzhu Jiang;Yong Li;Peng Zhou;Zhenyun Lan;Yunhao Lu;Chen Wu;Mi Yan
Advanced Materials 2017 Volume 29(Issue 48) pp:
Publication Date(Web):2017/12/01
DOI:10.1002/adma.201606499
AbstractBoosting power density is one of the primary challenges that current lithium ion batteries face. Alloying anodes that possess suitable potential windows stand at the forefront in pursuing ultrafast and highly reversible lithium storage to achieve high power/energy lithium ion batteries. Herein, ultrafast lithium storage in Sn-based nanocomposite anodes is demonstrated, which is boosted by pseudocapacitance benefitting from a high fraction of highly interconnected interfaces of Fe/Sn/Li2O. By tailoring the voltage window in the range of 0.005–1.2 V for the alloying/dealloying reactions, such Sn-based nanocomposite anodes achieve simultaneous ultrahigh rate capability, superlong cycling performance, and close-to-100% Coulombic efficiency. The nanocomposite anode delivers a high reversible capacity (≈420 mAh g−1) at 1 A g−1 for more than 1200 cycles, corresponding to only 0.016% per cycle of capacity decay. A reversible capacity of 350 mAh g−1 can be maintained at an ultrahigh current density of 80 A g−1, with 67.3% capacity retention relative to the capacity at 1 A g−1. This combination of pseudocapacitive lithium storage and spatially confined electrochemical reactions in Sn-based nanocomposite anode materials may pave the way for the development of high power/energy and long life lithium ion batteries.
Co-reporter:Tianzhi Yuan;Wenping Sun;Bo Xiang;Yong Li;Mi Yan;Ben Xu;Shixue Dou
Advanced Functional Materials 2016 Volume 26( Issue 13) pp:2198-2206
Publication Date(Web):
DOI:10.1002/adfm.201504849
Lithium ion batteries have attained great success in commercialization owing to their high energy density. However, the relatively delaying discharge/charge severely hinders their high power applications due to intrinsically diffusion-controlled lithium storage of the electrode. This study demonstrates an ever-increasing surface redox capacitive lithium storage originating from an unique microstructure evolution during cycling in a novel RGO–MnO–RGO sandwich nanostructure. Such surface pseudocapacitance is dynamically in equilibrium with diffusion-controlled lithium storage, thereby achieving an unprecedented rate capability (331.9 mAh g−1 at 40 A g−1, 379 mAh g−1 after 4000 cycles at 15 A g−1) with outstanding cycle stability. The dynamic combination of surface and diffusion lithium storage of electrodes might open up possibilities for designing high-power lithium ion batteries.
Co-reporter:Yinzhu Jiang;Shenglan Yu;Baoqi Wang;Yong Li;Wenping Sun;Yunhao Lu;Mi Yan;Bin Song;Shixue Dou
Advanced Functional Materials 2016 Volume 26( Issue 29) pp:5315-5321
Publication Date(Web):
DOI:10.1002/adfm.201600747
Rechargeable sodium ion batteries (SIBs) are surfacing as promising candidates for applications in large-scale energy-storage systems. Prussian blue (PB) and its analogues (PBAs) have been considered as potential cathodes because of their rigid open framework and low-cost synthesis. Nevertheless, PBAs suffer from inferior rate capability and poor cycling stability resulting from the low electronic conductivity and deficiencies in the PBAs framework. Herein, to understand the vacancy-impacted sodium storage and Na-insertion reaction kinetics, we report on an in-situ synthesized PB@C composite as a high-performance SIB cathode. Perfectly shaped, nanosized PB cubes were grown directly on carbon chains, assuring fast charge transfer and Na-ion diffusion. The existence of [Fe(CN)6] vacancies in the PB crystal is found to greatly degrade the electrochemical activity of the FeLS(C) redox couple via first-principles computation. Superior reaction kinetics are demonstrated for the redox reactions of the FeHS(N) couple, which rely on the partial insertion of Na ions to enhance the electron conduction. The synergistic effects of the structure and morphology results in the PB@C composite achieving an unprecedented rate capability and outstanding cycling stability (77.5 mAh g−1 at 90 C, 90 mAh g−1 after 2000 cycles at 20 C with 90% capacity retention).
Co-reporter:Wenping Sun, Xianhong Rui, Dan Zhang, Yinzhu Jiang, Ziqi Sun, Huakun Liu, Shixue Dou
Journal of Power Sources 2016 Volume 309() pp:135-140
Publication Date(Web):31 March 2016
DOI:10.1016/j.jpowsour.2016.01.092
•Bi2S3 was demonstrated to exhibit high-capacity sodium storage for the first time.•Bi2S3 nanorods were synthesized by a facile refluxing process.•Sodium storage in Bi2S3 is achieved by a conversion-intercalation mechanism.Exploring high-performance anode materials is currently one of the most urgent issues towards practical sodium-ion batteries (SIBs). In this work, Bi2S3 is demonstrated to be a high-capacity anode for SIBs for the first time. The specific capacity of Bi2S3 nanorods achieves up to 658 and 264 mAh g−1 at a current density of 100 and 2000 mA g−1, respectively. A full cell with Na3V2(PO4)3-based cathode is also assembled as a proof of concept and delivers 340 mAh g−1 at 100 mA g−1. The sodium storage mechanism of Bi2S3 is investigated by ex-situ XRD coupled with high-resolution TEM (HRTEM), and it is found that sodium storage is achieved by a combined conversion-intercalation mechanism.
Co-reporter:Yinzhu Jiang, Yong Li, Wenping Sun, Wei Huang, Jiabin Liu, Ben Xu, Chuanhong Jin, Tianyu Ma, Changzheng Wu and Mi Yan
Energy & Environmental Science 2015 vol. 8(Issue 5) pp:1471-1479
Publication Date(Web):23 Mar 2015
DOI:10.1039/C5EE00314H
Spatially-confined electrochemical reactions are firstly realized in a highly dense nanocomposite anode for high performance lithium ion batteries. The spatially-confined lithiation–delithiation effectively avoids inter-cluster migration and perfectly retains full structural integrity. Large reversible capacity, high rate capability and superior cycling stability are achieved simultaneously. This spatially-confined lithiation–delithiation offers novel insight to enhance cycling performance of high capacity anode materials.
Co-reporter:Chengcheng Xing, Dan Zhang, Ke Cao, Shumin Zhao, Xin Wang, Haiying Qin, Jiabin Liu, Yinzhu Jiang and Liang Meng
Journal of Materials Chemistry A 2015 vol. 3(Issue 16) pp:8742-8749
Publication Date(Web):13 Mar 2015
DOI:10.1039/C4TA07031C
A facile solution-based approach has been developed for the preparation of mackinawite FeS microsheet networks directly on Fe foil. It is found that sulfur sources significantly impact the uniformity and purity of the products, while ethylenediamine as a strong donor ligand plays an important role in the formation of FeS microsheet networks. For comparison, numerous FeS microspheres are obtained in the absence of ethylenediamine. The FeS microsheet networks deliver a promising Li storage capacity (772 mA h g−1 at the 1st cycle and 697 mA h g−1 at the 20th cycle), much higher than that of the FeS microspheres. The enhanced electrochemical performance of the FeS microsheet networks can be attributed to their layered structure and unique morphology, which possess a larger electrode–electrolyte contact area, shorter diffusion length of the ions and easier transportation of the electrons.
Co-reporter:Yinzhu Jiang, Yong Li, Peng Zhou, Shenglan Yu, Wenping Sun, and Shixue Dou
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 48) pp:26367
Publication Date(Web):November 18, 2015
DOI:10.1021/acsami.5b08303
SnO2 is regarded as one of the most promising anodes via conversion-alloying mechanism for advanced lithium ion batteries. However, the sluggish conversion reaction severely degrades the reversible capacity, Coulombic efficiency and rate capability. In this paper, through constructing porous Ni/SnO2 composite electrode composed of homogeneously distributed SnO2 and Ni nanoparticles, the reaction kinetics of SnO2 is greatly enhanced, leading to full conversion reaction, superior cycling stability and improved rate capability. The uniformly distributed Ni nanoparticles provide a fast charge transport pathway for electrochemical reactions, and restrict the direct contact and aggregation of SnO2 nanoparticles during cycling. In the meantime, the void space among the nanoclusters increases the contact area between the electrolyte and active materials, and accommodates the huge volume change during cycling as well. The Ni/SnO2 composite electrode possesses a high reversible capacity of 820.5 mAh g–1 at 1 A g–1 up to 100 cycles. More impressively, large capacity of 841.9, 806.6, and 770.7 mAh g–1 can still be maintained at high current densities of 2, 5, and 10 A g–1 respectively. The results demonstrate that Ni/SnO2 is a high-performance anode for advanced lithium-ion batteries with high specific capacity, excellent rate capability, and cycling stability.Keywords: anode; lithium-ion batteries; Ni; reaction kinetics; SnO2
Co-reporter:Yong Li, Shenglan Yu, Tianzhi Yuan, Mi Yan, Yinzhu Jiang
Journal of Power Sources 2015 Volume 282() pp:1-8
Publication Date(Web):15 May 2015
DOI:10.1016/j.jpowsour.2015.02.016
•A rational design of 3D-staggered metal-oxide nanocomposite structure was prepared.•Metal oxides are homogeneous distributed in a staggered manner.•The nanoparticles are rigorously confined at their original sites.•Integrity structure can be maintained due to little migration during cycling.•3D-staggered metal-oxide nanocomposite anodes demonstrate excellent cycle performance.Metal-oxide anodes represent a significant future direction for advanced lithium ion batteries. However, their practical applications are still seriously hampered by electrode disintegration and capacity fading during cycling. Here, we report a rational design of 3D-staggered metal-oxide nanocomposite electrode directly fabricated by pulsed spray evaporation chemical vapor deposition, where various oxide nanocomponents are in a staggered distribution uniformly along three dimensions and across the whole electrode. Such a special design of nanoarchitecture combines the advantages of nanoscale materials in volume change and Li+/electron conduction as well as uniformly staggered and compact structure in atom migration during lithiation/delithiation, which exhibits high specific capacity, good cycling stability and excellent rate capability. The rational design of metal-oxide nanocomposite electrode opens up new possibilities for high performance lithium ion batteries.
Co-reporter:Dan Zhang, Baoqi Wang, Yinzhu Jiang, Peng Zhou, Zhihui Chen, Ben Xu, Mi Yan
Journal of Alloys and Compounds 2015 Volume 653() pp:604-610
Publication Date(Web):25 December 2015
DOI:10.1016/j.jallcom.2015.09.068
•A series of Co3O4/KB composites cathodes in lithium oxygen batteries were prepared.•Co3O4/KB (80%) shows largest capacity, lowest overpotential and best stability.•The relationship of electrical conductivity and catalytic activity is studied.A series of Co3O4/Ketjen Black cathodes are fabricated by electrostatic spray deposition technique for Li–O2 batteries. A sluggish kinetics of oxygen reduction reaction and oxygen evolution reaction processes is noted either when Co3O4 is lacked or Ketjen Black is insufficient, which leads to much higher overpotentials between charge and discharge profiles. By contrast, with the optimal design in terms of electric conduction and catalytic activity, the Co3O4/Ketjen Black (80 wt%) composite achieves enhanced electrochemical performance with an initial discharge capacity of 2044 mAh g−1 and maintaining 33 cycles at a fixed capacity of 500 mAh g−1. The electrochemical characterization indicates that the improved Li–O2 battery performance may benefit from the highest oxygen reduction reaction and oxygen evolution reaction activity under this electro-chemically optimized composite. This work may shed light on the design principle of future cathode materials for Li–O2 batteries.
Co-reporter:Meijuan Hu, Yinzhu Jiang, Wenping Sun, Hongtao Wang, Chuanhong Jin, and Mi Yan
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 21) pp:19449
Publication Date(Web):October 20, 2014
DOI:10.1021/am505505m
Sodium ion batteries are attracting ever-increasing attention for the applications in large/grid scale energy storage systems. However, the research on novel Na-storage electrode materials is still in its infancy, and the cycling stability, specific capacity, and rate capability of the reported electrode materials cannot satisfy the demands of practical applications. Herein, a high performance Sb2O3 anode electrochemically reacted via the reversible conversion-alloying mechanism is demonstrated for the first time. The Sb2O3 anode exhibits a high capacity of 550 mAh g–1 at 0.05 A g–1 and 265 mAh g–1 at 5 A g–1. A reversible capacity of 414 mAh g–1 at 0.5 A g–1 is achieved after 200 stable cycles. The synergistic effect involving conversion and alloying reactions promotes stabilizing the structure of the active material and accelerating the kinetics of the reaction. The mechanism may offer a well-balanced approach for sodium storage to create high capacity and cycle-stable anode materials.Keywords: alloying; anode; conversion; Sb2O3; sodium ion battery
Co-reporter:Yinzhu Jiang, Dan Zhang, Yong Li, Tianzhi Yuan, Naoufal Bahlawane, Chu Liang, Wenping Sun, Yunhao Lu, Mi Yan
Nano Energy 2014 Volume 4() pp:23-30
Publication Date(Web):March 2014
DOI:10.1016/j.nanoen.2013.12.001
•A high-performance amorphous Fe2O3 anode is developed for lithium ion batteries.•Amorphization of TMOs may offer a new perspective for high performance LIB anodes.•A capacity of ~1600 mA h g−1 is sustained after 500 cycles at 1 A g−1.•A specific capacity of ~460 mA h g−1 is achieved using an ultra-large 20 A g−1.Despite their widespread application state-of-the-art lithium batteries are still highly limited in terms of capacity, lifetime and safety upon high charging rate. The development of advanced Li-ion batteries with high energy/power density relies increasingly on transition metal oxides. Their conversion reactions enable a combined high capacity and enhanced safety. Nevertheless, their practical application is severely limited by the insufficient cycling stability, poor rate capability and large voltage hysteresis which impact the lifetime and the performance of the battery. Here we report the exceptionally high-performance of an amorphous Fe2O3 anode, which largely outperforms its crystalline counterpart. Besides the advantageous narrow voltage hysteresis, this material exhibits a new breakthrough in terms of cycling stability and rate capacity. A highly reversible charge–discharge capacity of ~1600 mA h g−1 was observed after 500 cycles using a current density of 1000 mA g−1. A specific capacity of ~460 mA h g−1 was achieved using the ever reported large current density of 20,000 mA g−1 (~20 C), which opens venues for high power applications. The amorphous nature of Fe2O3 anode yields a unique electrochemical behavior and enhanced capacitive storage, which drives the overall electrochemical performance. This work demonstrates that amorphous transition metal oxides (a-TMO) based materials may offer a new perspective towards the development of high performing anodes for the next-generation of Li-ion batteries.
Co-reporter:Yinzhu Jiang, Meijuan Hu, Dan Zhang, Tianzhi Yuan, Wenping Sun, Ben Xu, Mi Yan
Nano Energy 2014 Volume 5() pp:60-66
Publication Date(Web):April 2014
DOI:10.1016/j.nanoen.2014.02.002
•A series of transition metal oxides is successfully demonstrated as anodes for sodium ion batteries.•The sodium uptake/extract is confirmed in the way of reversible conversion reaction.•The pseudocapacitance-type behavior is observed in the contribution of sodium capacity.•For Fe2O3 anode, a reversible capacity of 386 mAh g−1 at 100 mA g−1 is achieved over 200 cycles.•As high as 233 mAh g−1 is sustained even cycling at a large current–density of 5 A g−1.Sodium-ion batteries (SIBs) are attracting considerable attention with expectation of replacing lithium-ion batteries (LIBs) in large-scale energy storage systems (ESSs). To explore high performance anode materials for SIBs is highly desired subject to the current anode research mainly limited to carbonaceous materials. In this study, a series of transition metal oxides (TMOs) is successfully demonstrated as anodes for SIBs for the first time. The sodium uptake/extract is confirmed in the way of reversible conversion reaction. The pseudocapacitance-type behavior is also observed in the contribution of sodium capacity. For Fe2O3 anode, a reversible capacity of 386 mAh g−1at 100 mA g−1 is achieved over 200 cycles; as high as 233 mAh g−1is sustained even cycling at a large current–density of 5 A g−1.
Co-reporter:Dan Zhang;Yong Li; Mi Yan ; Yinzhu Jiang
ChemElectroChem 2014 Volume 1( Issue 7) pp:1155-1160
Publication Date(Web):
DOI:10.1002/celc.201402045
Abstract
Fe2O3 is a candidate material for anodes in Li-ion batteries due to its high theoretical capacity. However, the practical application of Fe2O3 is still limited by its sluggish conversion reactions. In this work, porous Fe2O3 films with homogeneously dispersed Ag nanoparticles are fabricated using a facile one-step electrostatic spray deposition technique. Both the unique, highly porous structure and the conducting Ag metal contribute to the outstanding electrochemical performance of the anode. The Fe2O3–Ag composite anode retains stable capacities of 1042 (0.1 C), 961 (1 C) and 857 mA h g−1 (5 C) over 100 cycles. When cycled at even higher rates, competitive capacities of 555 (15 C) and 509 mA h g−1 (20 C) are still acquired. This work might present opportunities to develop an oxide–metal anode with high capacity, long cycling life and good rate capability for Li-ion batteries.
Co-reporter:Yinzhu Jiang, Tianzhi Yuan, Wenping Sun, and Mi Yan
ACS Applied Materials & Interfaces 2012 Volume 4(Issue 11) pp:6216
Publication Date(Web):October 29, 2012
DOI:10.1021/am301788m
Porous SnO2/graphene composite thin films are prepared as anodes for lithium ion batteries by the electrostatic spray deposition technique. Reticular-structured SnO2 is formed on both the nickel foam substrate and the surface of graphene sheets according to the scanning electron microscopy (SEM) results. Such an assembly mode of graphene and SnO2 is highly beneficial to the electrochemical performance improvement by increasing the electrical conductivity and releasing the volume change of the anode. The novel engineered anode possesses 2134.3 mA h g–1 of initial discharge capacity and good capacity retention of 551.0 mA h g–1 up to the 100th cycle at a current density of 200 mA g–1. This anode also exhibits excellent rate capability, with a reversible capacity of 507.7 mA h g–1 after 100 cycles at a current density of 800 mA g–1. The results demonstrate that such a film-type hybrid anode shows great potential for application in high-energy lithium-ion batteries.Keywords: electrochemical spray deposition; graphene; lithium ion battery; thin films; tin oxide;
Co-reporter:Hao Gu, Yinzhu Jiang, Mi Yan
Journal of Alloys and Compounds 2012 Volume 521() pp:90-94
Publication Date(Web):25 April 2012
DOI:10.1016/j.jallcom.2012.01.043
The effect of defects in the diluted magnetic semiconductor (DMS) of Fe and Na co-doped ZnO nanoparticles was investigated. Structural characterizations revealed that Fe and Na ions enter into ZnO lattice without any secondary phase. The ferromagnetic behaviors at room temperature were found in all samples, which are attributed to the exchange via electron trapped oxygen vacancies (F-center) coupled with magnetic Fe ions. With the increase of the Na concentration, the oxygen vacancy mediated ferromagnetic state is enhanced. The observed correlation between the Na concentration, the carrier concentration and the magnetization revealed the role of the defect in tuning the ferromagnetism in the ZnO-based DMS system.Highlights► A new defect was introduced by Na co-doping into ZnFeO by sol–gel method. ► The study of structure indicates the ZnFeNaO system remains wurtzite ZnO structure. ► Carrier density and oxygen vacancy concentration changed after Na doping. ► Enhanced ferromagnetism in ZnFeNaO was observed compared with ZnFeO. ► The ferromagnetism is attributed to the defect induced exchange interaction.
Co-reporter:Chengcheng Xing, Dan Zhang, Ke Cao, Shumin Zhao, Xin Wang, Haiying Qin, Jiabin Liu, Yinzhu Jiang and Liang Meng
Journal of Materials Chemistry A 2015 - vol. 3(Issue 16) pp:NaN8749-8749
Publication Date(Web):2015/03/13
DOI:10.1039/C4TA07031C
A facile solution-based approach has been developed for the preparation of mackinawite FeS microsheet networks directly on Fe foil. It is found that sulfur sources significantly impact the uniformity and purity of the products, while ethylenediamine as a strong donor ligand plays an important role in the formation of FeS microsheet networks. For comparison, numerous FeS microspheres are obtained in the absence of ethylenediamine. The FeS microsheet networks deliver a promising Li storage capacity (772 mA h g−1 at the 1st cycle and 697 mA h g−1 at the 20th cycle), much higher than that of the FeS microspheres. The enhanced electrochemical performance of the FeS microsheet networks can be attributed to their layered structure and unique morphology, which possess a larger electrode–electrolyte contact area, shorter diffusion length of the ions and easier transportation of the electrons.
